S94.91 ICD-10-CM Code: Injury of unspecified nerve at ankle and foot level, right leg

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for S94.91 in the official ICD-10-CM tabular list, quoted as published.

Notes without a marker are published on S94.91 itself; “inherited from” names the category or block whose note applies here.

7th Character Guide

"The appropriate 7th character is to be added to each code from category S94"

• A — initial encounter
• D — subsequent encounter
• S — sequela

How the encounter character is assigned. “Initial encounter” means the patient is receiving active treatment for the condition — it is not limited to the first visit, and a different or new provider giving active treatment still assigns it. “Subsequent encounter” covers care during the healing or recovery phase after active treatment. “Sequela” is for complications or conditions that arise as a direct result of the original condition.

ICD-10-CM Official Guidelines for Coding and Reporting, Section I.C.19.a (paraphrased by MedCoder).

Variant codes in this family

S94.91XA, S94.91XD, S94.91XS

Character meanings are CMS's official 7th-character extensions for this family, as carried in each variant code's official description; variant codes are registry rows. The explanation of how the encounter character is assigned is MedCoder editorial, distinct from the official content above it.

Do Not Confuse With

Codes named in S94.91's own official notes, or sharing its encounter family, with what separates them. Each links to the full comparison.

• S94.91XA— Encounter relationship (Review)

  Same underlying diagnosis, different encounter phase.

  The same diagnosis at a different phase of care; one encounter takes one 7th character.

  Full comparison: S94.91 vs S94.91XA →

• S94.91XD— Encounter relationship (Review)

  Same underlying diagnosis, different encounter phase.

  The same diagnosis at a different phase of care; one encounter takes one 7th character.

  Full comparison: S94.91 vs S94.91XD →

• T20— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  Full comparison: S94.91 vs T20 →

• T32— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  Full comparison: S94.91 vs T32 →

• S82— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  Full comparison: S94.91 vs S82 →

• T33— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  Full comparison: S94.91 vs T33 →

Relationships are read from this code's own official notes and its encounter family; the wording of each distinction is MedCoder editorial. Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a.

Decision Points

The directives on this code's own record, as a pre-claim checklist.

1. A 7th character applies in this family. Confirm the documented encounter matches the character assigned. See the official 7th-character definitions and this code’s variants
2. Laterality is coded in this family. Confirm the documented side matches the code — the opposite-side siblings are in the relationships section. See the opposite-side sibling codes
3. 1 Code Also note — a second code may apply; the guidelines leave its sequencing to the circumstances of the encounter. See the Code Also notes
4. 4 Excludes2 entries — those conditions are not part of this code and may be reported additionally when documented. See the Excludes2 notes

Checklist rows are derived from this code's own official directives; the wording of each check is MedCoder editorial. The official notes themselves are in the sections each row links to.

Verify Before Coding

• Not billable as written — a more specific code is required: S94.91XA, S94.91XD, S94.91XS.
• Requires a 7th character. "The appropriate 7th character is to be added to each code from category S94" Options: S94.91XA, S94.91XD, S94.91XS

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

Other codes that name S94.91 or its code family, from the CMS ICD-10-CM tabular instructional notes. Tabular-note edges are stored at the code family level that carries each note.

Referenced by 12 Excludes2 notes: S74 — Injury of nerves at hip and thigh level (via S94.-), S80 — Superficial injury of knee and lower leg (via S94.-), S80-S89 — Injuries to the knee and lower leg (S80-S89) (via S94.-), S81 — Open wound of knee and lower leg (via S94.-), S82 — Fracture of lower leg, including ankle (via S94.-), S83 — Dislocation and sprain of joints and ligaments of knee (via S94.-), S84 — Injury of nerves at lower leg level (via S94.-), S85 — Injury of blood vessels at lower leg level (via S94.-), S86 — Injury of muscle, fascia and tendon at lower leg level (via S94.-), S87 — Crushing injury of lower leg (via S94.-), S88 — Traumatic amputation of lower leg (via S94.-), S89 — Other and unspecified injuries of lower leg (via S94.-).

These codes’ tabular lists name this diagnosis as distinct — both may be reported when both are documented.

Related Codes

Same condition, opposite side

Same category and title, differing only in which side of the body is affected.

S94.90 — Injury of unspecified nerve at ankle and foot level, unspecified leg (unspecified)Compare S94.91 vs S94.90 →, S94.92 — Injury of unspecified nerve at ankle and foot level, left leg (left)Compare S94.91 vs S94.92 →

Contextual Map

Every relationship of S94.91 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Run S94.91 with these 8 related codes in Claim Check

Hierarchy

• S00-T88 — Chapter 19: Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88) (S00-T88)[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Referenced by Excludes2 notes (12)

• S74 — Injury of nerves at hip and thigh level[Excludes2](via S94.-): “injury of nerves at ankle and foot level (S94.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• S80 — Superficial injury of knee and lower leg[Excludes2](via S94.-): “injuries of ankle and foot, except fracture of ankle and malleolus (S90-S99)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• S80-S89 — Injuries to the knee and lower leg (S80-S89)[Excludes2](via S94.-): “injuries of ankle and foot, except fracture of ankle and malleolus (S90-S99)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• S81 — Open wound of knee and lower leg[Excludes2](via S94.-): “injuries of ankle and foot, except fracture of ankle and malleolus (S90-S99)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• S82 — Fracture of lower leg, including ankle[Excludes2](via S94.-): “injuries of ankle and foot, except fracture of ankle and malleolus (S90-S99)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• S83 — Dislocation and sprain of joints and ligaments of knee[Excludes2](via S94.-): “injuries of ankle and foot, except fracture of ankle and malleolus (S90-S99)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• S84 — Injury of nerves at lower leg level[Excludes2](via S94.-): “injury of nerves at ankle and foot level (S94.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• S85 — Injury of blood vessels at lower leg level[Excludes2](via S94.-): “injuries of ankle and foot, except fracture of ankle and malleolus (S90-S99)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• and 4 more

Nearest codes (40)

• S94 — Injury of nerves at ankle and foot level[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• S94.22XS — Injury of deep peroneal nerve at ankle and foot level, left leg, sequela[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• S94.3 — Injury of cutaneous sensory nerve at ankle and foot level[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• S94.30 — Injury of cutaneous sensory nerve at ankle and foot level, unspecified leg[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• S94.30XA — Injury of cutaneous sensory nerve at ankle and foot level, unspecified leg, initial encounter[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• S94.30XD — Injury of cutaneous sensory nerve at ankle and foot level, unspecified leg, subsequent encounter[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• S94.30XS — Injury of cutaneous sensory nerve at ankle and foot level, unspecified leg, sequela[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• S94.31 — Injury of cutaneous sensory nerve at ankle and foot level, right leg[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• and 32 more

Change history

• FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

Common coding questions

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data

CMS/CDC ICD-10-CM FY2026 tabular list, index and tables, effective October 1, 2025 Release, file and checksum · Publisher’s page

Claim edits Official source data

CMS Definitions of Medicare Code Edits — v43.1 (April 2026) Release, file and checksum · Publisher’s page

Change history and date-of-service validity Official source data

CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page

Comparisons, relationships and the contextual map MedCoder structured relationship

Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears

Summary and FAQ answers MedCoder explanation

Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Nearest Codes in This Family

Official ICD-10-CM classifications closest to S94.91 in its code family, with their registry titles.

• S94.9 — Injury of unspecified nerve at ankle and foot level
• S94.90 — Injury of unspecified nerve at ankle and foot level, unspecified leg
• S94.90XA — Injury of unspecified nerve at ankle and foot level, unspecified leg, initial encounter
• S94.90XD — Injury of unspecified nerve at ankle and foot level, unspecified leg, subsequent encounter
• S94.90XS — Injury of unspecified nerve at ankle and foot level, unspecified leg, sequela
• S94.91XA — Injury of unspecified nerve at ankle and foot level, right leg, initial encounter
• S94.91XD — Injury of unspecified nerve at ankle and foot level, right leg, subsequent encounter
• S94.91XS — Injury of unspecified nerve at ankle and foot level, right leg, sequela
• S94.92 — Injury of unspecified nerve at ankle and foot level, left leg
• S94.92XA — Injury of unspecified nerve at ankle and foot level, left leg, initial encounter

View all codes in the S94 family